Injectable pharmaceutical formulations are well known in the art. Usually such formulations are in the form of dispersions such as colloids, emulsions and suspensions. More recently, sustained release injectable formulations comprising polymers have been used.
Interferons are a family of proteins which exhibit antiviral activity against certain viruses and anticancer activity against certain cancers. Interferons include natural or recombinant alpha (leucocyte), beta (fibroblast) and gamma (immune) interferon, but alpha interferons are preferred for use in the compositions of this invention. Human alpha interferon is a naturally occurring mixture of at least eleven components including those designated alpha.sub.1 and alpha.sub.2 interferon, the latter being more preferred in this invention. Human alpha interferon exhibiting biological properties similar to naturally occurring alpha interferon can be made by recombination methods. Rubenstein, Biochem. Biophys. Acta., 695, 5-16 (1982); Nagata et al., Nature, 284, 316-320 (1980); EP 32,134; and U.S. Patent 4,289,690 disclose methods for preparing alpha.sub.2 interferon. Also included within the scope of this invention are the so-called alpha hybrid interferons wherein fragments of two or more native alpha interferon species are joined (See, for example, EP 51,783). Parenteral administration of alpha.sub.2 interferon has been reported to be effective in the treatment of Kaposi's sarcoma, basal cell carcinoma, multiple myeloma and viral warts. The effective dose of alpha interferon can be easily determined by those skilled in the art.